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Topic Review
Doubling Time
The doubling time is time it takes for a population to double in size/value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time. When the relative growth rate (not the absolute growth rate) is constant, the quantity undergoes exponential growth and has a constant doubling time or period, which can be calculated directly from the growth rate. This time can be calculated by dividing the natural logarithm of 2 by the exponent of growth, or approximated by dividing 70 by the percentage growth rate (more roughly but roundly, dividing 72; see the rule of 72 for details and derivatiatives of this formula). The doubling time is a characteristic unit (a natural unit of scale) for the exponential growth equation, and its converse for exponential decay is the half-life. For example, given Canada's net population growth of 0.9% in the year 2006, dividing 70 by 0.9 gives an approximate doubling time of 78 years. Thus if the growth rate remains constant, Canada's population would double from its 2006 figure of 33 million to 66 million by 2084.
  • 13.3K
  • 28 Nov 2022
Topic Review
Bell Test Experiments
A Bell test experiment or Bell's inequality experiment, also simply a Bell test, is a real-world physics experiment designed to test the theory of quantum mechanics in relation to Albert Einstein's concept of local realism. The experiments test whether or not the real world satisfies local realism, which requires the presence of some additional local variables (called "hidden" because they are not a feature of quantum theory) to explain the behavior of particles like photons and electrons. To date, all Bell tests have found that the hypothesis of local hidden variables is inconsistent with the way that physical systems behave. According to Bell's theorem, if nature actually operates in accord with any theory of local hidden variables, then the results of a Bell test will be constrained in a particular, quantifiable way. If a Bell test is performed in a laboratory and the results are not thus constrained, then they are inconsistent with the hypothesis that local hidden variables exist. Such results would support the position that there is no way to explain the phenomena of quantum mechanics in terms of a more fundamental description of nature that is more in line with the rules of classical physics. Many types of Bell test have been performed in physics laboratories, often with the goal of ameliorating problems of experimental design or set-up that could in principle affect the validity of the findings of earlier Bell tests. This is known as "closing loopholes in Bell test experiments". In a novel experiment conducted in 2016, over 100,000 volunteers participated in an online video game that used human choices to produce the data for researchers conducting multiple independent tests across the globe.
  • 13.3K
  • 29 Nov 2022
Topic Review
Chemical Affinity
In chemical physics and physical chemistry, chemical affinity is the electronic property by which dissimilar chemical species are capable of forming chemical compounds. Chemical affinity can also refer to the tendency of an atom or compound to combine by chemical reaction with atoms or compounds of unlike composition.
  • 13.2K
  • 20 Oct 2022
Topic Review
Pingu
Pingu is a Swiss-British stop-motion clay animated children's comedy television series created by Otmar Gutmann and produced from 1990 to 2000 for Swiss television, and from 2003 to 2006 for British television by The Pygos Group (formerly Trickfilmstudio and Pingu Filmstudio). It centres on a family of anthropomorphic penguins who live at the South Pole; the main character is the family's son and title character, Pingu. The series originally ran for four series (each series made up of multiple seasons) from 7 March 1990 to 9 April 2000 on SF DRS and was then renewed for two more series from 1 August 2003 to 3 March 2006 on BBC Two. Pingu won a BAFTA award. Pingu was a worldwide hit, due to its lack of real spoken language: nearly all dialogue is in an invented grammelot "penguin language" referred to as 'Penguinese', consisting of babbling, muttering, and his characteristic sporadic loud honking noise, which can be popularly recognized as "Noot noot!" or other variants, stated to be "Noo, Noo!" by the defunct Pingu website's trivia page, accompanied by turning his beak into a megaphone-like shape. Within the first 4 series, all the characters were performed by Italian voice actor Carlo Bonomi, using a language of noises that he had already developed and used for the earlier Osvaldo Cavandoli's La Linea. In series 5 and 6, the Pingu cast was jointly voiced by David Sant and Marcello Magni. A Japanese reboot of the series, titled Pingu in the City, began airing on NHK-E on 7 October 2017.
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  • 12 Oct 2022
Topic Review
Toxic Ingredients in Skin Lightening Cosmetics
Skin lightening is defined as "the practice of using chemicals or any other product with depigmenting potential in an attempt to lighten skin tone or improve the complexion; these goals are achieved by decreasing the concentration of melanin to achieve a reduction in the physiological pigmentation of the skin". Products used to achieve this purpose are known as depigmenting, skin-lightening, skin-bleaching, skin-brightening or skin-evening agents. Skin-whitening products containing highly toxic active ingredients (in particular mercury derivatives, hydroquinone and corticosteroids) are easily found on the market; the use of these depigmenting agents can be followed by a variety of adverse effects, with very serious and sometimes fatal complications, and is currently an emerging health concern in many countries. 
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  • 26 May 2022
Topic Review
Dialysis (Biochemistry)
In biochemistry, dialysis is the process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrane, such as dialysis tubing. Dialysis is a common laboratory technique that operates on the same principle as medical dialysis. In the context of life science research, the most common application of dialysis is for the removal of unwanted small molecules such as salts, reducing agents, or dyes from larger macromolecules such as proteins, DNA, or polysaccharides. Dialysis is also commonly used for buffer exchange and drug binding studies. The concept of dialysis was introduced in 1861 by the Scottish chemist Thomas Graham. He used this technique to separate sucrose (small molecule) and gum Arabic solutes (large molecule) in aqueous solution. He called the diffusible solutes crystalloids and those that would not pass the membrane colloids. From this concept dialysis can be defined as a spontaneous separation process of suspended colloidal particles from dissolved ions or molecules of small dimensions through a semi permeable membrane. Most common dialysis membrane are made of cellulose, modified cellulose or synthetic polymer (cellulose acetate or nitrocellulose).
  • 13.2K
  • 07 Nov 2022
Topic Review
Underwater Wireless Sensor Networks
The underwater wireless sensor network (UWSN) is a network used to perform monitoring of tasks over a specific region; it is equipped with smart sensors and vehicles that are adapted to communicate cooperatively through wireless connections [1]. The surface sink retrieves the data from sensor nodes. The sink node has a transceiver that can control acoustic signals received from underwater nodes. The transceiver also can transmit and receive long-range radio frequency signals for communication with the onshore station. The collected data are used locally or connected to another network for a particular purpose [2].
  • 13.2K
  • 26 Oct 2020
Topic Review
Internet Archive
Coordinates: 37°46′56″N 122°28′18″W / 37.782321°N 122.47161137°W / 37.782321; -122.47161137 The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge".[notes 2][notes 3] It provides free public access to collections of digitized materials, including websites, software applications/games, music, movies/videos, moving images, and millions of books. In addition to its archiving function, the Archive is an activist organization, advocating a free and open Internet. As of April 2021, the Internet Archive holds over 30 million books and texts, 8.9 million movies, videos and TV shows, 649,000 software programs, 13,225,000 audio files, 3.8 million images, and 580 billion web pages in the Wayback Machine. The Internet Archive allows the public to upload and download digital material to its data cluster, but the bulk of its data is collected automatically by its web crawlers, which work to preserve as much of the public web as possible. Its web archive, the Wayback Machine, contains hundreds of billions of web captures.[notes 4] The Archive also oversees one of the world's largest book digitization projects.
  • 13.2K
  • 18 Oct 2022
Topic Review
Doctor of Engineering
The Doctor of Engineering, or Engineering Doctorate, (abbreviated Eng.D., D.Eng., D.Engr., Dr.Eng., or Dr.-Ing.) is a degree awarded on the basis of advanced study and research in engineering and applied sciences. In most countries, it is a terminal research doctorate. A DEng/EngD is equivalent to a PhD in engineering, but different in that it has a solid industrial base and an additional taught element. The DEng/EngD along with the PhD represents the highest academic qualification in engineering, and the successful completion of either in engineering is generally required to gain employment as a full-time, tenure-track university professor or postdoctoral researcher in the field. Individuals can use the academic title doctor, which is often represented via the English honorific "Dr”. DEng/EngD candidates submit a significant project, typically referred to as a thesis or praxis, consisting of a body of original applied research that may be in principle worthy of publication in a peer-reviewed journal. Candidates must defend this work before a panel of expert examiners called a thesis or dissertation committee.
  • 13.2K
  • 20 Oct 2022
Topic Review
Pickup Artist
Pickup artists (PUA), self-identified as dating coaches, the seduction community or the pickup community, is a movement of men whose goal is seduction and sexual success with women. The community exists through Internet newsletters and blogs, marketing (e.g. banner ads, seminars, one-on-one coaching), forums and groups, as well as local clubs, known as "lairs". The rise of "seduction science", "game", or "studied charisma" has been attributed to modern forms of dating and social norms between sexes which have developed from a perceived increase in the equality of women in western society and changes to traditional gender roles. Commentators in the media have described "game" as sexist or misogynistic.
  • 13.2K
  • 10 Oct 2022
Topic Review
Hydraulic Actuators
Hydraulic actuators are elements converting the energy of the working fluid into mechanical energy related to the reciprocating motion. The most frequently applied materials used in power hydraulics are described, and various surface modifications of the discussed elements, which are aimed at improving the operating parameters of actuators, are presented. The most frequently used materials for actuators elements are iron alloys. However, due to rising ecological requirements, there is a tendency to looking for modern replacements to obtain the same or even better mechanical or tribological parameters. Sealing systems are manufactured mainly from thermoplastic or elastomeric polymers, which are characterized by low friction and ensure the best possible interaction of seals with the cooperating element. In the field of surface modification, among others, the issue of chromium plating of piston rods has been discussed, which, due, to the toxicity of hexavalent chromium, should be replaced by other methods of improving surface properties.
  • 13.2K
  • 23 Mar 2021
Topic Review
Pashtun Tahafuz Movement
The Pashtun Tahafuz Movement (Pashto: پښتون ژغورنې غورځنګ‎, Urdu: پشتون تحفظ تحریک‎; abbreviated PTM), or the Pashtun Protection Movement, is a social movement for Pashtun human rights based in Khyber Pakhtunkhwa and Balochistan. Formerly called the Mahsud Tahafuz (or Protection) Movement, it was founded in May 2014 by eight students at Gomal University, Dera Ismail Khan as an initiative for removing landmines from Waziristan and other parts of the former Federally Administered Tribal Areas, affected by the war in North-West Pakistan.
  • 13.2K
  • 24 Oct 2022
Topic Review
Root-Finding Algorithm
In mathematics and computing, a root-finding algorithm is an algorithm for finding zeroes, also called "roots", of continuous functions. A zero of a function f, from the real numbers to real numbers or from the complex numbers to the complex numbers, is a number x such that f(x) = 0. As, generally, the zeroes of a function cannot be computed exactly nor expressed in closed form, root-finding algorithms provide approximations to zeroes, expressed either as floating point numbers or as small isolating intervals, or disks for complex roots (an interval or disk output being equivalent to an approximate output together with an error bound). Solving an equation f(x) = g(x) is the same as finding the roots of the function h(x) = f(x) – g(x). Thus root-finding algorithms allow solving any equation defined by continuous functions. However, most root-finding algorithms do not guarantee that they will find all the roots; in particular, if such an algorithm does not find any root, that does not mean that no root exists. Most numerical root-finding methods use iteration, producing a sequence of numbers that hopefully converge towards the root as a limit. They require one or more initial guesses of the root as starting values, then each iteration of the algorithm produces a successively more accurate approximation to the root. Since the iteration must be stopped at some point these methods produce an approximation to the root, not an exact solution. Many methods compute subsequent values by evaluating an auxiliary function on the preceding values. The limit is thus a fixed point of the auxiliary function, which is chosen for having the roots of the original equation as fixed points, and for converging rapidly to these fixed points. The behaviour of general root-finding algorithms is studied in numerical analysis. However, for polynomials, root-finding study belongs generally to computer algebra, since algebraic properties of polynomials are fundamental for the most efficient algorithms. The efficiency of an algorithm may depend dramatically on the characteristics of the given functions. For example, many algorithms use the derivative of the input function, while others work on every continuous function. In general, numerical algorithms are not guaranteed to find all the roots of a function, so failing to find a root does not prove that there is no root. However, for polynomials, there are specific algorithms that use algebraic properties for certifying that no root is missed, and locating the roots in separate intervals (or disks for complex roots) that are small enough to ensure the convergence of numerical methods (typically Newton's method) to the unique root so located.
  • 13.2K
  • 14 Oct 2022
Topic Review
Exonym and Endonym
An exonym (from Greek: éxō, 'outer' + ónuma, 'name'; also known as xenonym) is a common, external name for a geographical place, group of people, individual person, or a language/dialect, that is used only outside that particular place, group, or linguistic community. Exonyms not only exist for historico-geographical reasons, but also in consideration of difficulties when pronouncing foreign words. An endonym (from Greek: éndon, 'inner'; also known as autonym) is a common, internal name for a geographical place, group of people, or a language/dialect, that is used only inside the place, group, or linguistic community in question; it is their self-designated name for themselves, their homeland, or their language.
  • 13.2K
  • 18 Oct 2022
Topic Review
Cigarette Lighter Receptacle
The cigarette lighter receptacle (also called a cigar lighter receptacle or cigar lighter socket) in an automobile was initially designed to power an electrically heated cigarette lighter, but became a de facto standard DC connector to supply electrical power for portable accessories used in or near an automobile. While the cigarette lighter receptacle is a common feature of automobiles and trucks, as a DC power connector it has the disadvantages of bulkiness, relatively low current rating, and poor contact reliability. Examples of devices that can be operated from a cigarette lighter receptacle include lights, fans, beverage heating devices, and small motorized tools such as air compressors for inflating tires. Many portable electronic devices such as music players or mobile telephones use a cigarette lighter receptacle to recharge their internal batteries or to directly operate from the vehicle electrical system. Adapters for electronic devices may change voltage to be compatible with the supplied device. Devices that require alternating-current mains electricity can be operated with a plug-in inverter. Automobiles may provide several 12 V receptacles that are intended only to operate electrical accessories, and which cannot be used with a cigarette lighter. Car manufacturers may offer a cigarette lighter only as an optional extra-cost accessory. Usually, only one 12 V receptacle near the driver will be able to accommodate an actual cigarette lighter, with other receptacles designated as "12 V auxiliary power outlets" which are not physically able to power a lighter.
  • 13.2K
  • 24 Oct 2022
Topic Review
Wearable Devices for Stroke Prediction
Stroke ranks as one of the top first leading causes of death and disability worldwide, particularly for the most populous countries in Asia, Europe, and North America. The emerging wearable devices intended to monitor the physiological parameters, and the growth of machine learning applied to predict diseases, are promising solutions to prevent stroke and eventually predict stroke risk.
  • 13.1K
  • 30 Sep 2021
Topic Review
Interspecific and Intergeneric Hybridization
Interspecific hybridization occurs when crosses are made between different cultivated species belonging to the same genus. In contrast, the outcome of the combination of a distinct genus (cultivated species with their wild relatives) is known as intergeneric hybridization. These two approaches are the critical driving force in generating a different combination of hybrid lines, such as synthetic amphiploid lines, alloplasmic lines, and alien gene introgression lines, which act as a source of variation that leads to a broadening of the genetic variability and diversity of desired traits for crop improvement. However, the success rate of interspecific and intergeneric hybridization is comparatively low compared to intraspecific hybridization due to cross-incompatibilities mainly related to pre- and post-fertilization barriers. To overcome these challenges, in vitro techniques utilizing somatic hybridization or embryo rescue came into the picture and have proven to be the best alternative. Several embryo rescue techniques such as embryo culture, ovary culture, ovule culture, anther culture, and protoplast culture protect embryos from successful hybridization and from premature abortion. Due to the genomic shock, this successful hybridization induces genetic and epigenetic modification at the early stages (zygote formation and development) of hybrids and successive generations. Embryo rescue techniques such as immature embryo culture were used to develop an interspecific hybrid ACC between B. napus ‘Zhongshuang 9’ and B. oleracea ‘6m08.
  • 13.1K
  • 16 Sep 2022
Topic Review
Whataboutism
Whataboutism, also known as whataboutery, is a variant of the tu quoque logical fallacy that attempts to discredit an opponent's position by charging them with hypocrisy without directly refuting or disproving their argument. According to Russian writer, chess grandmaster and political activist Garry Kasparov, "whataboutism" is a word that was coined to describe the frequent use of a rhetorical diversion by Soviet apologists and dictators, who would counter charges of their oppression, "massacres, gulags, and forced deportations" by invoking American slavery, racism, lynchings, etc. Whataboutism has been used by other politicians and countries as well. Whataboutism is particularly associated with Soviet and Russian propaganda. When criticisms were leveled at the Soviet Union during the Cold War, the Soviet response would often use "and what about you?" style by instancing of an event or situation in the Western world. The idea can be found in Russian language: while it utilizes phrase "Sam takoi" for direct tu quoque-like "you too"; it also has "Sam ne lutche" ("not better") phrase.
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  • 18 Nov 2022
Topic Review
List of 2.4 GHz Radio Use
There are several uses of the 2.4 GHz band. Interference may occur between devices operating at 2.4 GHz. This article details the different users of the 2.4 GHz band, how they cause interference to other users and how they are prone to interference from other users.
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  • 07 Nov 2022
Topic Review
LifePower
LifePower, (LP), is an Applied Spiritual Philosophy that attempts to improve the lives of people whilst focusing on the personal life span, using and applying a variety of tools and exercises. LP focuses on the power of the self, in the relief of suffering from past traumatic experiences and seeks to meet a high level of consciousness, communication and serenity. It consists of several techniques as well as practices, called “drills” and draws on so-called 'Listening Processes'. The LP philosophy´ was founded and created by Dani Lemberger after he studied in-depth general philosophies on life, self and existence which in combination with studying Ron Hubbard´s philosophy, led him to develop the LifePower philosophy. LifePower focuses on the power of the self, in the relief of suffering from past traumatic experiences and seeks to meet a high level of consciousness, communication and serenity. It is based on the idea, that the human being is an eternal spirit. The philosophy founder claims that by applying it, a person can enhance their abilities, attain and gain personal power to create an enjoyable and meaningful life for themselves.
  • 13.1K
  • 27 Oct 2022
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